After installing Sp3, problem with search key

At the time of the installation of the sp3 on my desktop PC, after the decompression of the files and the examination of the PC,a pop-up opens with the following message: “the necessary search key was found in no active context of activation”. The update stops. I specify that my Windows xp is official, all the updates are done without problem on Windows update including the remote loading of this sp3. The same file sp3 was set up without any concern on my portable PC.
On the Microsoft support I did not find any help. That will annoy me much to format this PC because I am in multi boot thus that would be a little complicated. A research on google does not give anything except for problems with IE7: at home IE7 functions very well: does anyone know what is this necessary search key? Thank you

Download the SP3 again, and take the version for “data processing specialist” at Microsoft.

Thank you for your answer but can you say some more things on this “data processing specialist”? thank you by advance

Make sure your CD isn't scratched.

I had a similar problem when I tried to reinstall XP Pro on a friends computer. It halted the installation and wouldn't accept my key no matter what I tried. I ended up having to get a new CD.

Not sure if it helps in this situation, but you might want to check out the CD you are using.

If you are using Windows Update to install SP3, try downloading and installing the Network version.

You should scan your computer thoroughly for adware/spyware/viruses before you install SP3. I used several anti-spyware programs, AVG AntiVirus (free version) and Kaspersky online virus scanner.